Module: MapKit::ZoomLevel

Includes:
Math
Included in:
MapView
Defined in:
lib/map-kit-wrapper/zoom_level.rb

Overview

Ruby adaption of troybrant.net/blog/2010/01/set-the-zoom-level-of-an-mkmapview/

More here troybrant.net/blog/2010/01/mkmapview-and-zoom-levels-a-visual-guide/

Defined Under Namespace

Modules: ClassMethods

Constant Summary collapse

MERCATOR_OFFSET =

Total map width in pixels

268435456.0
MERCATOR_RADIUS =

Map radius in pixels

MERCATOR_OFFSET / PI

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

Include class methods



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# File 'lib/map-kit-wrapper/zoom_level.rb', line 200

def self.included(base)
  base.extend(ClassMethods)
end

Instance Method Details

#set_center_coordinates(center_coordinate, zoom_level, animated = false) ⇒ Object

Set the views center coordinates with a given zoom level

  • Args :

    • center_coordinate -> A MKMapPoint

    • zoom_level -> Zoom level as Int

    • animated -> bool



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# File 'lib/map-kit-wrapper/zoom_level.rb', line 212

def set_center_coordinates(center_coordinate, zoom_level, animated = false)
  # clamp large numbers to 18
  zoom_level = [zoom_level, 18].min

  # use the zoom level to compute the region
  span = self.class.coordinate_span_with_map_view(self, center_coordinate, zoom_level)
  region = MKCoordinateRegionMake(center_coordinate, span)

  # set the region like normal
  self.setRegion(region, animated: animated)
end

#set_map_lat_lon(latitude, longitude, zoom_level, animated = false) ⇒ Object

Set the views latitude and longitude with a given zoom level

  • Args :

    • latitude -> Float

    • longitude -> Float

    • zoom_level -> Zoom level as Int

    • animated -> bool



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# File 'lib/map-kit-wrapper/zoom_level.rb', line 233

def set_map_lat_lon(latitude, longitude, zoom_level, animated = false)
  coordinates = CLLocationCoordinate2DMake(latitude, longitude)
  set_center_coordinates(coordinates, zoom_level, animated)
end

#set_zoom_level(zoom_level, animated = false) ⇒ Object

Set the current zoom level

  • Args :

    • zoom_level -> Int or Float

    • animated -> Bool



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# File 'lib/map-kit-wrapper/zoom_level.rb', line 264

def set_zoom_level(zoom_level, animated = false)
  set_center_coordinates(self.region.api.center, zoom_level, animated)
end

#zoom_level ⇒ Object

Get the current zoom level

  • Returns :

    • Zoom level as a Float



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# File 'lib/map-kit-wrapper/zoom_level.rb', line 244

def zoom_level
  region = self.region.api
  center_pixel_x = self.class.longitude_to_pixel_space_x(region.center.longitude)
  top_left_pixel_x = self.class.longitude_to_pixel_space_x(region.center.longitude - region.span.longitudeDelta / 2)

  scaled_map_width = (center_pixel_x - top_left_pixel_x) * 2
  map_size_in_pixels = self.bounds.size
  zoom_scale = scaled_map_width / map_size_in_pixels.width
  zoom_exponent = log(zoom_scale) / log(2)
  zoom_level = 20 - zoom_exponent
  zoom_level
end